1. Field of the Invention
The present invention generally relates to a method for fabricating an n-type carbon nanotube device and, more particularly, to a method characterized in that thermal annealing and plasma-enhanced chemical vapor-phased deposition (PECVD) are employed to form a non-oxide gate layer on a carbon nanotube device. Therefore, the inherently p-type carbon nanotube can be used to fabricate an n-type carbon nanotube device with reliable device characteristics and high manufacturing compatibility.
2. Description of the Prior Art
In the nanotechnology era, it is an important issue to develop a carbon nanotube (CNT) logic device. Inherently, a carbon nanotube transistor exhibits p-type characteristics at room temperature.
Richard Smalley et al. have disclosed a conventional technique in xe2x80x9cChemical doping of individual semiconducting carbon-nanotube ropesxe2x80x9d (Physical Review B, Vol.61, No. 16), in which potassium ions are implanted into the carbon nanotube so as to provide sufficient electrons such that the carbon nanotube exhibts n-type characteristics. However, this method is not compatible with the state-of-the-art semiconductor manufacturing process.
Therefore, there is need in providing a method for fabricating an n-type carbon nanotube device, in which the p-type carbon nanotube exhibits n-type characteristics at room temperature and the method is compatible with the state-of-the-art semiconductor manufacturing process.
Accordingly, it is the primary object of the present invention to provide a method for fabricating an n-type carbon nanotube device, characterized in that thermal annealing and plasma-enhanced chemical vapor-phased deposition (PECVD) are employed to form a non-oxide gate layer on a carbon nanotube device.
It is the secondary object of the present invention to provide a method for fabricating an n-type carbon nanotube device, characterized in that the inherently p-type carbon nanotube can be used to fabricate an n-type carbon nanotube device with reliable device characteristics and high manufacturing compatibility.
In order to achieve the foregoing objects, the present invention provides a method for fabricating an n-type carbon nanotube device, comprising steps of: depositing an oxide film on a substrate; forming a first metal film on said oxide film; forming a carbon nanotube layer on said first metal film; depositing a gate layer covering said first metal film and said carbon nanotube layer; and forming a gate electrode on said gate layer.
The present invention further provides another method for fabricating an n-type carbon nanotube device, comprising steps of: forming a gate electrode in a substrate; depositing an oxide film on said substrate and said gate electrode; forming a first metal film on said oxide film; depositing a carbon nanotube layer on said first metal film; and depositing a gate layer covering said first metal film and said carbon nanotube layer.
Other and further features, advantages and benefits of the invention will become apparent in the following description taken in conjunction with the following drawings. It is to be understood that the foregoing general description and following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings are incorporated in and constitute a part of this application and, together with the description, serve to explain the principles of the invention in general terms.